4
dnsmx \- prints the MX records of fqdn
13
prints the MX records of
15
If there are no MX records,
17
prints an artificial MX record,
18
simulating the behavior of MTAs.
25
encounters a temporary problem
26
that prevents it from determining the list of MX records,
27
it prints an error message and exits 111.
38
http://cr.yp.to/djbdns.html